Characteristics of ultrasonication assisted assembly of gold nanoparticles in hydrazine reduced graphene oxide

Here we report a new ultrasonication assisted method for increased diffusion of a gold salt in hydrazine reduced graphene oxide (hrGO) sheets. Gold nanoparticles (AuNP) were formed through in situ reduction of diffused gold chloride within the hrGO sheets by sodium borohydride. Transmission electron microscopic (TEM) analysis confirmed uniform distribution of similar to 5-10 nm AuNP in hrGO sheets. Raman spectra of hrGO-AuNP showed an increase in the ratio of D-band to G-band intensity as well as the absence of a 2D band. This confirmed distortion of the multilayer assembly into much thin layers by the process of AuNP nucleation in the composite material. X-ray diffraction (XRD) spectra of hrGO-AuNP confirmed the presence of crystallite carbonic materials and AuNP by observing strong diffraction peaks of Au (111), Au (200), Au (220) and Au (311). UV-visible spectra of the oxide hrGO-AuNP showed a spectral shift of 21 nm in reduced graphene oxide which confirmed the binding of AuNP with hrGO. X-ray photo electron spectroscopy (XPS) analysis revealed 13.4, 69.3, 13 and 2.3% mass proportions for gold, carbon, oxygen and nitrogen, respectively in hrGo-AuNP. XPS analysis also showed an increase in sp(3) carbons as compared to sp(2) carbons in C1s after gold nucleation in hrGO. The I-V response of hrGO remained unaffected by the nucleation of AuNP in the hrGO composite material. This method may be useful to address the challenges associated with the incorporation of metals into reduced graphene oxide without chemical functionalization of inert surfaces.